A blood gas analysis data acquisition system is being developed to continuously measure the partial pressure of oxygen and carbon dioxide and the level of oxygen saturation in extracorporeal mammal blood flow in association with a membrane lung. The system is controlled by a microprocessor which commands and acquires data from transducers for PO2, PCO2, and O2 saturation and probe temperature. Values are calculated from these inputs and displayed in units of mmHg pressure and percent of total saturation.